Implemented SelectMultiple in django.newforms.widgets

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3958 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/newforms/widgets.py

@@ -2,16 +2,26 @@
 HTML Widget classes
 """
 
-__all__ = ('Widget', 'TextInput', 'PasswordInput', 'HiddenInput', 'FileInput', 'Textarea', 'CheckboxInput', 'Select')
+__all__ = (
+    'Widget', 'TextInput', 'PasswordInput', 'HiddenInput', 'FileInput',
+    'Textarea', 'CheckboxInput',
+    'Select', 'SelectMultiple',
+)
 
 from django.utils.html import escape
 from itertools import chain
 
+try:
+    set # Only available in Python 2.4+
+except NameError:
+    from sets import Set as set # Python 2.3 fallback
+
 # Converts a dictionary to a single string with key="value", XML-style.
 # Assumes keys do not need to be XML-escaped.
 flatatt = lambda attrs: ' '.join(['%s="%s"' % (k, escape(v)) for k, v in attrs.items()])
 
 class Widget(object):
+    requires_data_list = False # Determines whether render()'s 'value' argument should be a list.
     def __init__(self, attrs=None):
         self.attrs = attrs or {}
 
@@ -70,14 +80,31 @@ class Select(Widget):
             final_attrs.update(attrs)
         output = [u'<select %s>' % flatatt(final_attrs)]
         str_value = str(value) # Normalize to string.
-        for option_value, option_label,  in chain(self.choices, choices):
+        for option_value, option_label in chain(self.choices, choices):
             selected_html = (str(option_value) == str_value) and ' selected="selected"' or ''
             output.append(u'<option value="%s"%s>%s</option>' % (escape(option_value), selected_html, escape(option_label)))
         output.append(u'</select>')
         return u'\n'.join(output)
 
 class SelectMultiple(Widget):
-    pass
+    requires_data_list = True
+    def __init__(self, attrs=None, choices=()):
+        # choices can be any iterable
+        self.attrs = attrs or {}
+        self.choices = choices
+
+    def render(self, name, value, attrs=None, choices=()):
+        if value is None: value = []
+        final_attrs = dict(self.attrs, name=name)
+        if attrs:
+            final_attrs.update(attrs)
+        output = [u'<select multiple="multiple" %s>' % flatatt(final_attrs)]
+        str_values = set([str(v) for v in value]) # Normalize to strings.
+        for option_value, option_label in chain(self.choices, choices):
+            selected_html = (str(option_value) in str_values) and ' selected="selected"' or ''
+            output.append(u'<option value="%s"%s>%s</option>' % (escape(option_value), selected_html, escape(option_label)))
+        output.append(u'</select>')
+        return u'\n'.join(output)
 
 class RadioSelect(Widget):
     pass